Device for tensioning the presser foot of automatic embroidering machines



Nov. 1, 1966 E. NIEKRAWIETZ DEVICE FOR TENSIONING THE PRESSER FOOT OF AUTOMATIC EMBROIDERING MACHINES 2 Sheets-Sheet 1 Filed Oct. 12, 1965 [/VVE/VTOR [RM/V lWE/(M 14/572 85/ E. NIEKRAWIETZ 3,282,237

ENSIONING THE PRESSER FOOT 2 Sheets-Sheet 2 [mm/70R.- 2 W/A/ MEKRA W/ETZ Ill LI III III II UHHHMF III II fiH H H HMMHH Nov. 1, 1966 DEVICE FOR T OF AUTOMATIC EMBROIDERING MACHINES Filed UCt. 12, 1965 United States Patent Oil-ice 3,282,237 Patented Nov. 1, 1966 3,282,237 DEVICE FOR TENSIONING THE PRESSER FOOT F AUTOMATIC EMBROIDERING MACI-IINES Erwin Nielrrawietz, Hamburg, Germany, assrgnor to Marco Sticlrantomaten-Gesellschaft Marksclreffel & Co., Hamburg-Wandsbelr, Germany, a firm Filed Oct. 12, 1965, er. No. 45,137 Claims priority, application Germany, Mar. 16, 1965, M 51,025 1 Claim. (Cl. 112-236) This invention relates to a device for tensioning the presser foot of automatic embroidering machines, the presser foot being slidably guided on a needle bar and subjected to spring tension.

Tensioning devices of this kind are known. In these devices a spring is fixed between the presser foot and the housing of the embroidering machine. When the presser foot contacts the feed plate with the material to be embroidered positioned thereon, and when the needle bar is in the lowest position, the spring tension is practically canceled or this tension is existent only in the case of an adjusted pretension. Due to this, heavy materials to be embroidered, such as felt, leather and rubber-coated materials, will adhere to the needle and be lifted by the upwardly moving needle so that no loop of the upper thread can be formed on the needle and faultystitches may occur.

In the highest position of the needle the spring tension is then largest, and to this tension the pre-tension must still be added. This causes the driving members to be heavily loaded.

In order to overcome this deficiency, and to obtain in the lowest position of the presser foot and the needle bar the largest pressure of the presser foot on the material to be embroidered, it is suggested according to the invention to arrange one or more springs between the presser foot and the needle bar.

Such a spring may be embodied in a tension spring fixed with its upper end to the upper portion of the presser foot and with its lower end to the lower portion of the needle bar. Alternatively, the spring may be a pressure spring fixed with its upper end to the upper portion of the needle bar and with its lower end to the lower portion of the presser foot.

In the lowest position of the needle, in which the stitch is formed, the material to be embroidered is held down by, the presser foot with the highest possible pressure. When the needle bar moves upwardly, the presser foot remains on the material to be embroidered until the spring is relieved and then the needle bar takes the presser foot along with it.

One embodiment of the invention will nOW be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is an elevational view of the needle bar and the presser foot in the lowest position;

FIG. 2 is a side View, partly in section, of the arrangement of FIG. 1, and

FIG. 3 is an elevational view of the needle bar and the presser foot in the highest position.

With reference now to the drawings, a presser foot 2 is slidably guided on a needle bar 1. The needle bar 1 can i be moved to and fro through a wheel 3, a connecting rod 4 connected eccentrically to the wheel 3 and a driving block 5 fixedly mounted on the needle bar 1. The presser foot 2 is guided on the needle bar 1 at its upper end by means of a bridge 6 and in its middle portion by a bend 7.

Arranged between the bridge 6 of the presser foot 2 and a disc 8 on the needle bar 1 is a pair of tension springs 9 which have the tendency to keep the distance between the bridge 6 and the disc 8 small.

As the needle bar 1 is brought by the driving block 5 into the position shown in FIG. 3, the presser foot 2 is also lifted through the bridge 6 and a foot portion 10 of the presser foot is lifted off the material 11 to be embroidered. In this position of the needle bar 1 the needle 12. has passed through the foot portion 10 and is situated above the foot portion 10. The material 11 to be embroidered can now be brought into the desired position. The springs 9 are practically relieved.

During the downward movement of the needle bar 1 the presser foot 2 follows this movement since the tension of the springs 9 increases. When the foot portion 10 con- I tacts the material to be embroidered, the needle 12 moves down into the position shown in FIGS. 1 and 2 and the springs 9 are imparted their highest tension with which they press the foot portion 10 of the presser foot 2 firmly onto the material to be embroidered. In the lowest position of the needle the formation of the stitch is effected. When the needle bar 1 moves upwardly, the foot portion 10 first remains under high tension on the material to be embroidered, so that the same cannot be taken along upwardly. The tension of the springs decreases only gradually.

In order to avoid too heavy an impact of the foot portion 10 on the material 11 to be embroidered, and to prevent the material lll from being hammered to pieces, an adjustable elastic buffer 13 is provided. The bridge 6 is arranged to strike against the buffer 13.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claim rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claim are therefore intended to be embraced therein. For example, instead of the tension springs 9 one or more pressure springs may be arranged. The pressure springs must then be fixed with their upper ends to the upper portion of the needle bar and with their lower ends to the lower portion of the presser foot.

I claim:

An embroidering machine having a presser foot, a needle bar, and a device for tensioning the presser foot comprising means slidably guiding said presser foot on said needle bar and at least one tension spring arranged between the presser foot and the needle bar in such a manner that during the contact of the presser foot with material to be embroidered and in the lowest position of the needle bar the presser foot can be pressed against the material to be embroidered with the largest spring tension, said tension spring being fixed with its upper end to the upper portion of the presser foot and with its lower end fixed to the lower portion of the needle bar, and an ad- 3,282,237 3 4 justable elastic buffer for intercepting the presser foot at 2,355,700 8/1944 Blewett 112236 the moment of contacting the material to be embroidered. 2,633,093 3/1953 Russell 112236 References Cited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 5 516,741 12/ 1920 France.

220,779 10/ 1897 Wemple 112227 A 823,442 6/1906 Rodman 112 236 JORDAN FRANKLIN, Przmar y Exammer. 1,018,622 2/1912 Karle 112236 PATRICK D. LAWSON, Examiner. 

